Wire rope prestressing machine



Sept. 26, 1944. D. D. SYMMES 2,359,170

WIRE ROPE PRESTRESSING MACHINE Filed June 17, 1943 2 Sheets-Sheet l IN VEN TOR.

Sept. 26, 1944. SYMMES 2,359,170

WIRE ROPE PRESTRESSING MACHINE Filed June 17, 1943 2 Sheets-Sheet 2 INVEN TOR. fla/v/a 0. firMMia Patented Sept. 26, 1944 WIRE ROPE PRESTRESSING MACHINE Daniel D. Symmes, West Haven, Conn, assignor to The American Steel and Wire Company of New Jersey, a corporation of New Jersey Application June 17, 1943, Serial No. 491,232

Claims.

This invention is a machine for use in wire rope manufacture to prestress wire rope. The machine is of the continuous type, providing means for engaging the opposite ends of a length of the rope and applying stress to this length while the rope continuously travels, the machine having the advantage that the stressed length may be made very large, to permit high speed operation of the machine, without involving the need for wasting so large a front end portion of the rope as is usual, in such instances, when prior art machines are used.

Other advantages will become apparent from the following disclosure.

The accompanying drawings illustrate a speciflc example of the machine, the various figures being as follows:

Figure 1 is a top view;

Figure 2 is a side View;

Figure 3 is an enlarged detailed view from Figure 2; and,

Figure 4 is a side view of Figure 3 in partial vertical section.

More specifically, rope R, from a pay-off reel l, carrying the rope, is bent around a system of sheaves 2 journaled by a frame 3 in such a fashion that the rope first passes around a capstan 4 and is then formed in a large number of horizontal loops storing a relatively large length of the rope, the latter then going to a capstan 5 and, from there, to a powered take-up reel 6.

The capstan 4 is provided with a brake drum 1' having a frictionally engaging brake band 8 to which braking force is applied by a forcemultiplying lever system 9 receiving its force by way of a balancing beam 10 provided with fixed weights H and, also, an adjustable weight l2 in screw threaded engagement with a threaded shaft l3 powered by a reversing electric motor H.

The capstan 5 is powered by a constant speed motor l5, through a gear reduction unit I6, to

' pull the rope from the capstan 4 rotatively restrained by the brake. When the capstan 5 pulls the rope it causes it to continuously travel through a relatively large length, stored in loop form by the sheaves 2, so the rope is stressed throughout this length, high speed operation being permissible because the large siz of this length causes each portion, of the rope to remain under stress for the proper time period even though the rope is traveling at high speed.

Heretofore, a machine, of the type under disclosure, could not provide proper stress throughout the long rope length, after initial threadin until a substantial portion of the rope had traveled to the capstan 5, and it was necessary to waste the resulting unstressed portion. The disclosed machine avoids this because the capstan 5 need only take up the slack, in the various rope loops, to create full stress in the length.

a sheave I'm forced against the rope R, in a defleeting direction, by a draft band IIb worked by a draft band drum i8 receiving force from a second larger draft band drum l9 worked by a draft band 20 provided with force applying weight H. The rope deflection is measured by a gear 2! turned by the draft band drum l9 and meshing with a pinion 23 turning a hand 24 which plays over a calibrated dial 25.

Automatic operation of the machine is efiected by providing an abutment 26 moving with movement of the draft band 2|] and working upper and lower limit switches 21 electrically connected with the motor M, by the conventional system, so that when the upper one of the limit switches 21 is operated, due to too little stress in the rope, the motor l4 operates to move the balancing weight l2 in a direction applying more force to the band 8; and when the lower one of the limit switches 21 is operated, due to too much tautness in the rope, the motor I4 is reversely operated to move the balancing weight I 2 in the direction releasing some of the force applied the brake band 8. In this fashion the rope is continuously provided,

within narrow limits, with any predetermined,

constant stress.

To overcome the startin inertia of the brake drum 1 and band 8, the balancing beam I 0 may be momentarily raised at the start of the machine's operation, to momentarily release the force on the brake band. This may be done manually by lifting the beam, or, more conveniently, by providing a foot pedal 28 working a tension rod 29 fixed to the beam on the side of its fulcrum opposite its weighted side. This arrangement permits the machine to be stopped, whenever desired, and restarted without breaking the rope being processed.

I claim: 1. Strand stressing apparatus including two rotative elements for engaging the opposite ends of a relatively large length of the strand to he stressed, means for supporting said length against yielding lateral deflection of any material extent,

a frictional brake restraining rotation of one of of a relatively large length of the strand to be stressed, means for supporting said length against yielding lateral deflection of any material extent,

.a frictional brake restraining rotation of one of the elements, and a motor for rotatively powering the other of the elements to cause it to pull the strand from the element restrained by the brake and stress the strand, the brake having means for adjusting its-restraining force and'the apparatus including a device. for measuring the stress in the stressed strand length, with a system rendering said means automatically responsive to operation of this device to maintain the stress in the stressed strand length at a predetermined value.

3. A wire rope iprestressing machine including a capstan, a friction brake for the capstan, means for adlustably applying operating force to the brake, a second capstan, a motor for powering the second capstan, means for guiding a relatively large length of the rope from one capstan to the other for prestressing and for supporting said length-against yielding lateral deflection of any material extent, and means for measuring the stress in the prestressed rope, length.

4. A wire rope prestressing machine including a capstan, a friction brake for the capstan, means for adjustably applying operating force to the brake, a second capstan, a motor for powering the second capstan, means for guidin a relatively large length of the rope from one capstan to the other for prestressing and for supporting said length against yielding lateral deflection of any material extent, and means for measuring the stress in the prestressed rope length, the machine including a system rendering the first named means automatically responsive to operation of the stress measuring means to maintain the prestressing stress at a practically constant predetermined value.

5. A wire rope prestressin machine including a capstan, a friction brake for the capstan, means for adjustably applying operating force to the brake, a second capstan, a motor for powering the second capstan, means for guiding a relatively large length of the rope from one capstan to the other for prestressing and for supporting said. length against yielding lateral deflection of any material extent, and means for measuring the stress in the prestressed rope length, the machine including a system rendering the first named means automatically responsive to operation of the. stress measuring means to maintain the prestressing stress at a practically constant predetermined value, said motor being a constant speed motor.

DANIEL D. SYMMES. 

